adapted or appropriate to the purpose or circumstances; fit; suitable

the proper time to plant strawberries.

conforming to established standards of behavior or manners; correct or decorous

a very proper young man.

fitting; right

It was only proper to bring a gift.

strictly belonging or applicable

the proper place for a stove.

belonging or pertaining exclusively or distinctly to a person, thing, or group.

strict; accurate.

in the strict sense of the word (usually used postpositively)

Shellfish do not belong to the fishes proper. Is the school within Boston proper or in the suburbs?

Grammar .

(of a name, noun, or adjective) designating a particular person or thing and written in English with an initial capital letter, as Joan, Chicago, Monday, American.

having the force or function of a proper name

a proper adjective.

normal or regular.

belonging to oneself or itself; own.

Chiefly British Informal . complete or thorough

a proper thrashing.

Ecclesiastical . used only on a particular day or festival

the proper introit.

Heraldry . (of a device) depicted in its natural colors

an oak tree proper.

Informal .

excellent; capital; fine.

good-looking or handsome.

Mathematics . (of a subset of a set) not equal to the whole set.

Archaic . of good character; respectable.

Informal . thoroughly; completely.

Ecclesiastical . a special office or special parts of an office appointed for a particular day or time.

noun

comeliness , correctness , decentness , decorousness , decorum , propriety , respectability , respectableness , seemliness